London rapper Cbiz – real name David Osadebay – and three other men were last year charged with his murder.

Their trial at the Old Bailey saw the prosecution claim the four men had carried out the Church Road drive-by shooting in revenge for stolen jewellery. All four were acquitted in January after the trial collapsed due to insufficient evidence.

On Thursday (9 March) – the one year anniversary of his death – Tetlow's mother gave an emotional appeal for anyone with information on her son's murder to come forward.

Pamela Humphrey said: "The 9 March 2017 is one year to the day that my son Oliver Tetlow was cruelly murdered in cold blood – shot dead in a senseless and tragic case of mistaken identity.

"We are appealing again for you to come forward if you know anything, saw anything or can help in any way with the ongoing investigation. This appeal is not only for us, but for your family, your friends, innocent bystanders who could be murdered like Oliver was. We are searching for justice, to feel safe in the knowledge that whoever killed Oliver will be taken off our streets.

"We have lived through a terrible year of grief and sadness, having a talented young man with so much to look forward to in life torn from us. Every day I miss my son, my family miss him, Oliver's friends miss him, every day we think of him, every day we all grieve for him. Our pain goes on."

Oliver Tetlow was gunned down on 9 March, 2016 in a hail of bulletsMet Police

In addition to the renewed appeal, a reward of £10,000 is being offered by the charity Crimestoppers for information leading to the arrest and successful conviction of the person or persons responsible for the murder.

Tetlow was pronounced dead at the scene after he was shot 14 times just before 10pm of 9 March, 2016.

Detectives believe he was gunned down with an automatic weapon by a male in a dark coloured vehicle, which then drove off south along Church Road, towards Harlesden town centre. Neither the vehicle nor the weapon has been recovered.

Police originally believed the killing was ordered by 30-year-old flamboyant rapper Osadebay in "revenge" after a video was posted online mocking him following the theft of his gold bling.

Tetlow was said to be the innocent victim of that revenge after being mistaken for an individual who featured in the video, who was also said to be a member of the Church Road Soldiers gang.

But on 10 January the trial collapsed after the judge ruled there was insufficient evidence to allow a jury to convict Osadebay or 20-year-old co-defendant Mohammed Siamino.

Two other defendants – Romarne Young, 22, of Stafford Road, South Kilburn, and Jahmico Trott, 29, from Hulme, Manchester – had already been acquitted earlier in the trial.

Tetlow's mother urged people with any information to come forward, saying she was seeking justice "not only for us, but for our community".

She said: "Despite all the efforts by the police, CPS and courts, so far no convictions have been made. We continue to pray that justice will be done and although it will never lessen the loss we feel, it will bring some small comfort to relieve our suffering, our pain, our grieving.

"Please, please help us. Some witnesses have already come forward and we admire them all for their courage. Those who haven't felt able to come forward before, please help yourself; release yourself from the terrible burden you carry."

Detectives say they have spoken to more than 100 witnesses and trawled through hours of CCTV in a bid to catch those responsible for Tetlow's murder.

They said "a significant amount of information" has been obtained and passed to officers, but they have "yet to receive the vital piece of information that would finally put the killer or killers behind bars".

They also revealed they are pursuing a line of inquiry that suggested the the murder weapon – believed to be a Skorpion submachine gun – may have been brought down to London from Manchester, before returning back to the city the same night.

Detective Chief Inspector Mark Lawson, of the Met Police, said: "Oliver had simply been going about his business on the night of his murder when he was targeted and gunned down in what we still believe was a case of mistaken identity. A young man has tragically lost his life and it is only right that we remain resolute in our efforts to convict those responsible.

"This is the first anniversary of Oliver's death and I am keen to hear from anyone who has any information or who was at the scene of the incident. You may not have come forward at the time of the murder, now is the time to do so, please do not remain silent. A year is a long time to go without answers and I would ask that you to take a moment and think about the devastation that has been caused to Oliver's family.

Oliver Tetlow was shot 14 times in Harlesden, north west London

"I am also directly appealing to the friends and family shielding those responsible. Now is not the time to stay silent. If you have the slightest indication that those you know were involved in the murder I would encourage you to get them to hand themselves into the police.

"In the days after the murder the firearm used to kill Oliver would have no doubt been passed on to someone to hide or to keep safe and there is a possibility that this gun has exchanged hands since.

"It is of paramount importance first and foremost that this weapon is taken off the streets and secondly I would like to appeal to anyone who knows who the gun was handed to or knows where it is now to come forward and speak to us.

"We are pursuing a line of inquiry with another police force as to where the gun came from and to its current whereabouts but it is vital that if you hold any information no matter how small, you do come and speak with us.

"This is very much still a live investigation, and despite the recent acquittal of the four men we continue to explore new lines of inquiry. Allegiances can change rapidly in a year and I am very keen to hear from anyone who for whatever reason didn't speak to us at the time of the murder."

Anyone who witnessed the incident or has any information is asked to contact the incident room on 020 8358 0200 or via Twitter @MetCC. Alternatively, you can contact Crimestoppers anonymously on 0800 555 111.